Field of the Invention
The present invention relates to a power unit. More particularly, to a power unit including a gear shifting device for a saddle riding type vehicle.
Description of Background Art
Japanese Patent No. 4499083, for example, discloses a structure in a conventional saddle riding type vehicle wherein a driving source for actuating a gear shifting device is disposed below a crankcase in a power unit of an internal combustion engine housing the gear shifting device in the crankcase.
In the structure described in Japanese Patent No. 4499083, because the driving source for the gear shifting device is disposed so as to be displaced below the crankcase, the center of gravity can be lowered. When such a driving source for the gear shifting device is disposed so as to be displaced below the crankcase, a structure is adopted in which the gear shifting device and the driving source are separated from each other with a large distance therebetween. Therefore, for example, the power transmission efficiency of the driving source for the gear shifting device and the shape and arrangement of other peripheral parts are affected. Thus, the degree of freedom for the structure and arrangement of the peripheral devices is limited.